Method of forming cap screws or the like fasteners



NOV. 15, RQSENBIERG I 2,136,524

METHOD OF FORMING CAP SCREWS OR THE LIKE FASTENERS v Filed July 28, 1957 4 Sheets-Sheet l -f z 57.5.

Nov. 15, 1938. H ROSENBERG 2 METHOD OF FORMING CAP SCREWS OR THE LIKE FASTENERS --'Filed July 28, 937 4 Sheets '-Sheet 2 Zlwuc "from NOV. t H ROS R METHOD OF FORMING CAP SCREWS OR THE LIKE FASTENERS lNVENTOR firM/l/vfiosavafee Nov. 15, .1938.

VH.RO$ENBERG METHOD OF FORMING CAP SCREWS OR THE QIKE FASTENERS Filed Jul 28, 1957 4 Sheets-Sheet 4 INVENTOR .bQ'YMANfiOJE/VETRG Patented Nov. 15, 1938 UNITED STATES. PATENT OFFICE METHOD OF FORMING CAP SCREWS OR THE LIKE FASTENERS Herman Rosenberg, New York, N. Y. Application July 28,1937, Serial No. 156,217

9 Claims. (01. 10-10) The present invention relates to improvements in cap screws of the socket head type and in particular to novel methods of producing the same, this application constituting a continuation in part of my copending application for socket head cap screws or the like fasteners, Serial No. 122,456, filed January 26, 1937.

The primary purpose of these improvements is to provide a fastener member of the type mentioned with means, forming a part of its construction, for locking against or preventing undesired unturning of the fastener once it has' been turned home in the body receiving the same.

More specifically, a further object of this invention is the formation of knurls or ribs upon the face of the fastener head and as an incident thereto causing the metal to flow in a manner to form a series-of teeth-like projections, extending from the head in a longitudinal direction of the fastener body.

A still further object resides in the formation of the locking teeth, as above referred to, so that they will project from the head more or less in a general direction opposite the direction of turning movement when introducing the fastener body into its operative position, whereby any reverse or unscrewing movement of the body will tendto cause the projections to more deeply penetrate into the face of the object against which the under-face of the fastener head is pressed, thereby establishing a self-acting interlock of increasing effectiveness the greater the, tendency of the fastener to unscrew forany reason.

In carrying out the foregoing objectives, 1 may employ any one of various methods to produce the desired result,either by specially form-L ing the fastener blank previous to rolling or forming the die in' a special manner or both,all Having the common feature of causing the metal of the head'material-to flow and form projections which. protrude from the seating face of the head while simultaneously forming knurls or ribs on the side of the head.

Other and further objects and advantages of the invention (will be hereinafter set forth and defined by the ap-' I the novel features thereof pended claims.

In the drawings: Fig. l is a side elevation of a blank from which one embodiment of my invention is formed;

Fig. 2 is a view showing the blank being rolled between dies of an automatic thread-forming machine,- the dies and mounting therefor being shown in section;

Fig. -3 is a perspective view of the formed cap screw and one of the rib rolling dies;

Fig. 4 is a transverse section of one of the dies for forming the cap screw from the blank of Fig.- l.

Fig. 5 is a vertical, fragmentary, sectional view showing the locking teeth or projections embedded in the face of the material into which the screw is introduced and screwed home;

Fig.6 is a side elevation of a modified form of fastener in which the knurls or ribs are formed only on a portion of the face of the head;

Fig. 7 is' a side elevation of the blank from which the cap screw of Fig. 6' is produced;

Fig. 8 is a sectional view of the die for producing the screw of Fig. 6;

vFig. 9 is a side elevation of a straight side blank for use in conjunction with the die shown in Fig. 10;.

.Fig. 10 is a sectional view of one of the dies for rolling the blank of Fig. 9;

Fig. .11 is a sectional view of the screw produced by the blank and die of Figs. 9 and 10, showing the taper form of the ribs and the screw in operative position;

Fig. 12 is a modified blank;

Fig. 13 is a sectional view of a die for producing a partially. knurled face and projecting teeth;

Fig. 14 is a side elevation of another modification illustrating a herring-bone type of knurling rib;

Fig. 15 shows a plan View of a portion of a machine for carrying out onemethod of knurl-' ing;

Fig. 16 is an enlarged sectional view of the knurl holder, screw and collet used in the machine of Fig. 15;

Fig. .17 is a sectional view of a punch press construction for carrying out my method of knurling; and

Fig. 18 is a plan view of the base section of the press. I z Like reference characters designate corresponding parts in the several figures of the drawings. 1

Referring to the drawings, and specifically describing the simplest-methodof producing my cap screw invention, I designates a blank conflange projection is important, particularly the presentation of the sharp edge at the base of the head for reasons hereinafter pointed out. At the top portion of this face, the head is chamfered.

I as at 4, leading to a finishing bevel 5 at the extremity.

The blank thus formed is placed in a conventional threading machine to form threads la on the shank, after which the blank is placed in the hopper of an automatic thread roller and fed into position between a pair of knurling dies 6 and 1 having .upon their operating faces diagonal ribs 6a and la and intermediate grooves for forming corresponding ribs 8 and grooves on the face 2 of the head.

The operation of these dies is well known, die 6 being mounted in the stationary die holder ll of the machine, while the die 1 is held in a reciprocating gate l2. Filler blocks l0 cooperate with the dies and take care of the different lengths of heads.

Movement of the gate l2 causes the blank to.

.the simultaneous rolling and compression, will also flow or throw down the metal of the annular projection or flange 3 into sharp pointed teeth 9 on the lower edge of the screw head due to the sharpness of the edge of the flange 3. In this connection it is to be noted that the shape and extent of these teeth are predetermined by the size and shape of the flange 3 on the preformed blank. This blank, therefore, is an important article of manufacture for the purpose of forming fastener devices of the type disclosed herein.

These teeth are so shaped and arranged by the diagonal grooves of the dies that they will act as ratchet teeth and will penetrate the material into which the bolt is introduced when the bolt is screwed homepr tends to unscrew, either from vibration or any other cause. This condition is shown in Fig. 5 of the drawings. The heat treating process which the entire bolt undergoes after completion also hardens and strengthens the pro-- jecting teeth so that they are strong enough to perform this interlocking action.

In Fig. 6 a slight modification of the construction is illustrated in that the ribbing or knurling 8' of the head is produced only on the lower portion of the face of the bolt together with the teeth projections 9' extending therefrom. In this form of the fastener, the chamfer 4 is not provided, but in the preferred form the chamfer is important in that it prevents the formation of sharp burrs at the top of the head during the knurling.

A blank substantially shaped as shown in Fig. 7 is used in conjunction with a pair of dies, one of which is shown in Fig. 8, to accomplish this result. When the. blank is constructed as in this form, the conventional form of dies with parallel ribs on their faces are used.

However, it is to be understood that I may accomplish the same result by using a plain blank, that is, a blank with parallel or straight sides as shown in Fig. 9, and constructing the die as shown in Fig. 10 with knurl-producing ribs I5 which taper upwardly slightly. When the blank is rolled between a pair of dies so constructed, said dies will cause the metal to flow downwardly of the head, under the compressive and rolling action, and produce parallel knurls with projecting teeth It is to be noted that the angular shape of this as shown in Fig. 11, the grooves between the ribs being slightly deeper at the base of the head, as clearly een at l5.

Using this same principle of construction of die with sh rt ribs I6 in conjunction with a blank l1: shown in Fig. 12, having a reduced diameter at the base of the head as indicated at IT, I am able toproduce similarly a partially knurled head fastener, corresponding to that shown in Fig. 6.

In Fig. 14, I have illustrated another modification of the knurling which here takes the form of a herring-bone 8a, the teeth So being present as in the other constructions.

I desire it to be understood, however, that the knurled head fastener invention may be produced by other types of machines than the conventional screw threading apparatus hereinbefore set forth and in the use of which the metal of the head is caused to flow in a substantially longitudinal direction of the fastener by rolling and compression of the head between the rolling dies. In other words, as distinguishing from the foregoing process, I may cause the knurl forming dies to move in a direction parallel to the axis of the blank so that the dies will push the metal from the head in a longitudinal direction as they are rotated to thereby produce the knurls and the projecting teeth.

One machine for this purpose is illustrated in Figs. 15 and 16. Referring to this construction, a screw blank such as shown in Fig. 9 and designated I is brought into line with and pushed into a spring collet 20 mounted in the spindle 2|, by a push-on finger 22 carried in the turret 23 that is mounted with its axis in a horizontal position on the turret slide 24. This slide rides back and forth on the dovetail way 25 in the bed 26 of the machine. The spindle 2| runs in roller bearings mounted directly in the machine bed and is driven at a constant speed by the cone pulley 21, driven by a belt 28. v

Another belt drives the back shaft and through a series of clutches, cams and gears (not shown) intermittently drives the spur gear 29 mounted on the slide 24 on the shaft of which is also mounted a bevel gear 30 which meshes with the bevel gear 3| on the shaft 32. Fastened to said shaft is a disk 33 carrying a roller 34 that engages one of the radial slots 35 in the disk 36, said disk being fast on the shankv of the turret 23 causing the turret to turn part of a revolution and bring, alternately, a push-on finger and knurl holder in line with the collet. The turret is locked in each part of its revolution by a locking pin 31 engaging bushings 38 in the turret. The pin is operated by the lever 39 pivotally mounted at 40. One end of the lever is fastened to the pin while the roller 4| mounted in the other end of said lever rides against the face of. a cam 42 fixed to the shaft 32. I

As seen in the enlarged section of Fig. 16, the knurl holder 43 is of the adjustable type and fastened to a shank 44 by a screw 45, the said shank of the holder being placed alternately with the pushon fingers, in the holes 46 in the turret. Theknurling dies 41 turn freely on pins 48 in the adjustable holders 49, said holders being threaded and slotted at 50 and 5| respectively, to care for the different size heads of the screw blanks and to adjust the angle of the knurling on the head in cases where the ribs on the dies are parallel to the axis. As shown in the drawings, the ribs on the dies are the same as those shown on the ward in a direction parallel to the head of the screw, theknurling dies as they rotate, push the metal toward the base of the head, forming both the knurls or the ribs and the teeth-like projections extending therefrom.

These fasteners may be produced on still another type of apparatus and reference will now be made to Figs. 17 and 18 showing a punch press. In this apparatus the blank for forming the fastener, such as shown in Fig. 9 is placed in a holder 52 which is rotatably mounted in a block 53 fastened in the ram 54, said ram being slidable up and down in gibs 55 of the punch press 56. The holder 52 is held in the block 53 by a pin 51 and bears againsta'thrust bearing 58 which allows it to turn freely when being forced through the die. v

A'die holder 59 is mounted on the bed 60 oi. the press and held in position by means oi. clamps ii. The die 62 is knurled or ribbed as at 63 and shouldered at 64. A cap 65 holds the die in position against the die holder and against the stripper mechanism which is also mounted in the die holder. stripper :to allow for different size dies. stripper, mechanism comprises a holder 61, strippers 68 and a cover 69. The cover is fastened to the holder by means of screws [0. --The holder has three grooves i n whichgslide the three strippers that are forced inwardly by means of a circular spring H. g

In the operation of this machine, as the hea of the screw blankpasses through the knurling die, the spiral ribs cause the holder containing the blank to follow and, the die being in a line parallel to the-screw axis, the metal flows upwardly, thereby causing theteeth-like projections to form at the base of the head.

After passing through the die, the head of the blank enters the stripper and forces the strippers 68 apart until the head reaches its lowest position and the stripper closes in. Then in the upward movement of. the holder the strippers remove the blank.

In the completion 'of the screw fasteners, it is to be understood that the sockets "in the heads maybe formed in the usual manner and at the customarystage of operation. -Also the knurls may be produced at other angles than that shown herein, though it' is preferable that the pitch of the ribs be from right to left so that the teeth will point rearwardly with reference to the direction of rotation of the screwing operation. Other modifications may be made without departing from the spirit of the invention and within the scope of the appended claims.

Having thus described my invention, what I claim as new and. desire to secure by Letters Patent is:

1. The method of producing cap screws of the class described which consists of the step of forming a headed blank with a predetermined oii'standing annular projection and rolling the head between grooved dies to cold flow the projection into a series of projections extending longitudinally from the seating face of the head.

2. The method of producing cap screws or bolts which consists of reducing a headed blank to the desired shape with an enlargement at the base 0 of the head, and rolling the head between dies having diagonal rib-forming grooves therein and A spacer block 66 is placed below the This 'therebyformin g ribs on the face of the head and flowing "the material of the enlargement into spaced projections extending at an angle and head, and rolling the head betjween grooved dies to flow the flanged portions into sharp pointed projections extending in an axial direction from the base of the head.

4. The method of forming fastening devices of the class described, which comprises the steps of forming a headed blank with a chamfer at the top of the head and a sharp-edged annular flange at the bottom of the head, and rolling the, head between dies having knurl forming faces to effect knurling of-the head and the formation of the said flange into sharp projections extending from the seating face of the head.

5. The method of producing cap screws or like fasteners which comprises the steps of forming a headed blank with an annular flange at the base of the head presenting a sharp edge around said base and rolling the head between dies having diagonal rib-forming grooves cooperative with at least a portion of the face of the head and with the flange thereby forming diagonal ribs on the face and aligned projections extending from the seating face of the head.

6. The method of producing knurled screw fasteners which comprises the steps of providing a knurling die with angularly'disposed knurling ribs, compressing the fastener blank to be knurled and simultaneously moving the die and blank axially and rotatively relative to each other in a manner to cause the material of the blank to flow into angularly arranged ribs on the blank.

'7. The method of producing knurled screw fasteners which comprises the steps of. providing a knurling die with angularly disposed knurling ribs, moving a headed fastener blank and said die while in contact both longitudinally and angularly relative to each other, said die and blank being so shaped as to cause flow of the material of the head into angularly related knurls and projections extending from the seating face of the head.

8. The method of producing knurled fastener devices of the class described comprising the steps of. providing angularly disposed knurling ribs on the die having a gradually increasing height from end to end, and rolling'a headed-fastener blank between a pair of such dies to cause the material of the head to flow both angularly and longitudinally into angular knurls with projections extending therefrom and from the seating face of the fastener head.

9. The method of producing knurled fastener devices of the class described comprising the steps of providing angflrlarly disposed knurling ribs on the die, mounting said die to rotate about its axis, contacting said die with the head of a fastener blank. and moving said die and head rotatively and longitudinally to effect flow of the material of the head both angularly and longitudinally into ribs on the side and projec tions extending axially oi the head.

HEYMAN ROSENBERG. 

